Automatic safety device for cinematographic apparatus



Mar. 27, 1923. 1,449,595. H. FAHLENBERG.

AUTOMATIC SAFETY DEVICE FOR CINEMATOGRAPHIC APPARATUS. FILED DEC-6,1919.

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Patented Mar. 27, 1923.

UNITED STATES PATENT OFFICE.

HERMAIIN FAHLENBERG, OF PANKOW, NEAR BERLIN, GERMANY, ASSIGNOR TO RICHARD A. HANSEMANN, OF BERLIN, GERMANY.

AUTOMATIC SAFETY DEVICE FOR CINEMATOGRAPHIC APPARATUS.

Application filed December 6, 1919. i Serial No. 343,097.

To all whom z'tmay concern:

Be .it known that I, HERMANN FAHLEN- BERG, a citizen of Germany, residing at and whose post-oflice address is Pankow, near Berlin, Pestalozzistrasse 29, Germany, have invented certain new and useful Improvements in Automatic Safety Devices for Cinematographic Apparatus, of which the following is a specification.

If, in cinematograph apparatus a bad, glued joint or an irregularitylof the film shifting device gives rise to a snapping of the film it will be pulled out of its guides by the motor and, if the apparatus continues 1 5 working, it will be crumpled up into a ball so as to become unfit for further use. The film is also liable to be snapped by getting jammed and stuck in some part of its system of guides.

The object of the present invention is to provide a guard or safety device for cinematographic apparatus which, in the case of the film being broken or getting ammed in its guides, automatically opens the circuit through which current is supplied to the electric lantern and the motor by which the film mechanism is driven. This is accomplished by arranging a loaded member to be supported by the film. and to move in one direction or the other and switch off the current when the film snaps or becomes stuck.

A manner of carrying out the invention is illustrated in the drawing which represents an interior view of a part of a cinematographic apparatus in which the film and the safety device are in evidence.

A mercury switch a of a known type is revolubly mounted on a pivot 11 within the range of a rod 6. The rod 72 carries two adjustablecstops h, h and is suspended on a pulley c from the endless film e which i travels over the fixed pulleys 0?, 03 (Z d; The rod is also loaded at the bottom with a weight g. 7

Now if the film snaps at f, or at any other point, the rod 6 loaded with the weight g is pulled downward in its guide and its stop it strikes against the holder of the mercury switch a causing the switch to be swung down about its pivot 2'. This causes the globule is of mercury tofiow into the inclined right hand end of the tube of the mercury switch thus severing the connection between the positive and negative terminals. Through these terminals the current is supplied to the electric lantern and motor of the apparatus, these parts being omitted to simplify the drawing.

If the film becomes stuck at any part of its guiding mechanism the film band lying between the 'said part and the film shifting device will be pulled tauter than usual and this will result in the rod 6 being pulled upward and in the lower stop k of the same striking against the cradle or holder of the mercury switch a. The left end of this switch will thus be tilted down causing the globule is of mercury to move to the end of the tube and open the circuit.

I claim:

1. In a cinematographic apparatus having a motor driven film, a weighted member freely suspended from a loop in the film, said member being adapted to be moved in opposite directions when said loop increases or diminishes in length and a switch in the circuit of said motor normally in a closed position and adapted to be opened by the movement of said member in either direction, thereby to open the switch when the film is abnormally loose or abnormally taut.

2. In a cinematographic apparatus hav ing a motor driven film, a weighted rod suspended from the film, a switch in the circuit of said motor adapted to be directly actuated by said rod, guiding members for the film, meansfor raising the rod and opening the switch when the film is held back by a guide member, and a member on the said rod for opening the switch when the film fails to support the rod.

In testimony whereof I have afllxed my signature in presence of two witnesses.

HERMANN FAHLENBERG. Witnesses:

PAUL MAsoow, PAUL GAEDA. 

